Production of i-inositol



Patented Jan. 14, 1947 1 J 2,414,365

UNITED STATES PATENT OFFICE Milton Elkin, Dorchester, Mass, and Carl M. Meadows, Nanuet, N. Y., assignors, by mesne 1 assignments, to AmericanCyanamid Company,

New York, N. 3. a corporation of Maine N Drawing. Application May 28, 1942, 1

Serial No. 444,926

6 Claims. (0]. 260- 631) ThlS inventlon relates to the production of The process will be further illustrated in con i-mositol (inactive lnositol) and more nart1cujunction with the following specific examples It larly relates to an improved method fo1 obtaining should be understood, however, that the exami-inositol by hydrolyzing salts of phytic acid ples are given for the pur pose of illustration and In the past it has been proposed to isolate 5 not by way of limitation. line, or neutral hydrolysis. (U. S. Patent No. EXAMPLE 1 2,112,553 and Industrial and Engineering Chem- HYDROLYSIS IN A NEAR NEUTRAL MEDIUM Ten gram samples of phytates in. near neutral esses have not been entirely satisfactory in that Solutions prepared as indicated in the table that an: improved method for hydrolyzing salts drolysis were determined in order to calculate the Table I N s 1 0 (AH) so H Initial Final Tlnlatal Per cent 0. amp e in 50 cc. H] T 4 g 4 p inorganic inorganic p 05- I phosphorus phosphorus phorus hydrolysls Gms. Mg. Mg. July.

Z1 p I 625 1,150 I30 10 .9 s 654 1,150 .82 of lower temperatures and pressures than the EXAMPLE 2 previously known methods.

It is also an advan 30 tage of this invention that complete hydrolysis HYDWLYSIS IN AN ACID MEDIUM of phytic acid salts and a higher over-all recovery The experiments outlined in Table II follow the of i-inositol is obtained unde same procedure as those of Example 1 except conditions. It is a further that the autoclave time was varied and that the vention that the hydrolysis hydrolysis was carried out in an acid medium Initial Final Total Per cent Sample in 60 cc. H1O (NHOSO4 pH inorganic inorganic phosdrol Sis phosphorus phosphorus phorus y y s3 l 9s. 1 1 564 1,076 50. B .47 V 3a 804 1,016. 73. neutral and acidic solu n theabove table indicate that the monium salts.

sample (2) containing ammonium sulfate was In carrying out our invention phytates are subcompletely hydrolyzed, showing a 12% improvejected to a hydrolytic treatment in the presence -ment over the sample (1) containing no amof an ammonium salt. In general anaquecus 4 monium sulfate. This degree of superiority is solution or suspension of a phytate, which soluaccounted for'without taking into consideration tion may be nearly neutral or acidic, has added the possibility of complete hydrolysis having octhereto an ammomum salt after which the solu curred in less than eight hou1s It is pa1t1cularly tion is autoclaved for from 1 to 15 hours at from significant therefore to note in the experiments about 10 to 20 pounds pressure. in which the samples (1A and 2A, 1B and 2B) previously, the ratio of were autoclaved for four hours and 2 /2 hours the difference in hydrolysis increased to 14.4% and 22.9%, respectively.

In the foregoing specific examples ammonium and sodium phytates were employed as thestarting materials. other phytates may be employed, including calcium phytate, barium phytate, magnesium phytate, potassium phytate, iron phytate, strontium phytate, manganese phytate, hexa-copper phytate, octa-silver phytate, or any other metal salt of phytic acid. I

We prefer to ammonium sulfate as the ammonium salt the hydrolysis of phytates because of its cheapness and ready availability. It should be distinctly understood, however, that ammonium salts, such as ammonium chloride, ammonium nitrate, ammonium ace tate, ammonium phosphate, or other ammonium acid salts, may be employed in our process for catalyzing the hydrolytic splitting of phytates into i-inositol and phosphates or phosphoric acid.

The time of autoclaving', the pressure, and the pH of the phytate solution or suspension may be varied within reasonable limits from those specifically illustrated. The optimum conditions may be determined experimentally for any particular phytate, and the hydrolysis then carried out under the most economical conditions. In general, the time of autoclaving may be varied from one to fifteen hours and the pressures from to pounds per square inch. The pH of the starting solution may be varied from about 6.90 to about 2.5, the best results usually being obtained when the solution at the beginning has a pH of about 3.

The crude phytic acid salts obtained from steep waters produced in starch are amenable to our hydrolysis process;

' of great commercial importance bep the most abundant sources of phytin is from this steep water obtained as a by-product in the production of corn starch. As pointed out ammonium salt to phytate may be varied to permit operations employing a wide range of temperatures, pressures, and times, to give satisfactory hydrolysis of the phytates. In most instances rather mild conditions wherein the pH of the solutions has been adjusted to 3.0 to about 3.5 result in complete hydrolysis in an economicalperiod of time. While the ratio of phytate to ammonium salt is not particularly critical, we have found that with commercially available crude phytates the concentration of ammonium salt should be not less than. about 1 partper five parts of water and that: the phytate suspended in the solution be not less than about one part per fiveparts water. This suspension should then be adjusted toan acidity of approximately pH 3 and autoclaved at about 15 pounds pressure for fifteen hours or such time as is shown by phosphorusdeterminations to be required for complete hydrolysis. The pH adjustments of the suspension may be made utilizing "any satisfactory acid and any satisfactory base. We have found that sulfuric acid and sodium hydroxide are entirely satisfactoiy for making the pH adjustments.

The i-inositol prepared in accordance with our process may be recovered from the hydrolysis mixture by any satisfactory method. We have found that the i-inositol may be isolated in good use Instead of these phytates various the manufacture of corn ment which comprises which comprises from about 15 to 20 "range of about 3.0 to about yields by a process which comprises diluting the solution with an equal volume of water and adding calcium oxide with vigorous stirring to distinct alkalinity. The resultant suspension is treated with decolorizing charcoal and filtered hot. If desired, the solid residue may be resuspended in a volume of water equal to the filtrate, stirred vigorously, while heating for about thirty minutes. The solution is then filtered and the two filtrates combined and concentrated to about one-fifth to one tenth of the original volume. An equal volume of ethyl alcohol is added to this concentrate and filtered, the precipitate being washed with 5% alcohol. This alcoholic filtra-te is concentrated to a syrup and diluted with four to five volumes of glacial acetic acid, after which crystallization is allowed to proceed in a cold room. The precipitatedi-inositol is washed with glacial acetic acid and recrystallizedfrom warm 56% acetic acid.

It is obvious that the above description and examples are intended to be illustrative only and that they may be varied or modified to a considerable extent without departing from the spirit of the invention or sacrificing the advantages thereoi- We do not, therefore, intend to limit ourselves to the specific embodiments herein set forth except as indicated in the appended claims.

What we claim is:

1. In the method for the preparation of i-inositol by hydrolysis of phytates the improvement which comprises carrying the hydrolysis out by heating a phytate in the presence of an ammonium acid salt in an aqueous solution having an acidic reaction.

2. In the method for the preparation or i-inositol by hydrolysis of phytates the improvement hydrolyzing a phytate in an aqueous solution having a pH of from about 2.5 to 6.9 and containing an ammonium acid salt by subjecting said phytate to a heat treatment at pounds pressure.

3. In the method for the preparation of i-inositol by hydrolysis of phytates the improvement which comprises subjecting an aqueous solution of a phytate and an ammonium salt, wherein the pI-I of said solution falls within the range of about 3.0 to about 6.9, to a heat treatment at from about 15 to 20 pounds pressure.

esIn the method for the preparation of'iinositol by hydrolysis ofphytates the improvement which comprises subjecting an aqueous solution of a phytate and ammonium sulfate;

wherein the pH of said solution falls within the range of about 3.0 to about 6.9, to a heat treatment at from about 15 to 20 pounds pressure.

5. In the method for the preparation of iinositol by hydrolysis of phytates the improvesubjecting an aqueous solution of sodium phytate and ammonium sulfate, wherein the pH of said solution falls within the range of about ment at from about 15 to 20 pounds pressure.

6. In the method for the preparation of i-inositol by hydrolysis ofphytates the improvement which comprises subjecting an aqueous solution of ammonium phytate and ammonium sulfate, wherein the pH. of said solution falls within the 6.9, to a heat treatment at from about 15 to 20 pounds pressure.

MILTON ELKIN', CARL M. MEADOWS.

3.0 to about 6.9, to a heat treat- 

